Nitrous Instillation on a Cobalt
Nitrous is all about increasing acceleration on demand. It has its advantages and disadvantages. Let me start with the down side. It voids your warranty. A back fire can blow your engine apart. There is no warning that a back fire is coming. Go to UTube and type in “Cobalt Nitrous” (it’s the first one titled 14.6 2.2L and watch a backfire blow the guys intake manifold into pieces and damage his hood and front fascia. He probably had head damage also as the back fire originates either in the piston or the head and flashes backs to the fuel / nitrous source. Backfires are the result of two factors, spark timing and internal cylinder temperature. Too much spark advance or lack of spark retarding along with increased surface temperature of the pistons, cylinder walls, or spark plug tip will create the right combination for pre-ignition. These factors can be controlled in three ways. The first is the amount of nitrous introduced. A 35hp shot is not as volatile as a 100hp shot therefore it is more tolerant to heat and spark timing. Second is internal heat, holding any size shot for 4 seconds verses 8 seconds will keep the heat down inside. Also time in between shots should be separated by several minutes so that the heat can transfer from the surface of the cylinder wall, through the block so that the coolant can collect that heat and disperse it through the radiator. Third is timing. At present I cannot find an aftermarket chip that will retard timing only when the motor is being sprayed. There are “Nitrous Chips” out there but there is no external connection to the chip to tell it “I’m spraying – retard timing now”. The factory chip is fine up to a 75 hp shot. The 35 & 50hp shots are fine for street and track use. The 75hp shot I only use for short blasts on the street. In second gear once you reach 3,500 rpm you can then spray from 3,500 to 6,000. You never want to get close to the 6,500 rpm red line as the rev limiter will shut the spark off and this WILL cause a backfire. Also I’m pretty nervous with the 75hp shot as not only do you really feel a strong increase in G force, the engine screams twice as load as normal and you can clearly hear every ignition of fuel nitrous mixture in every cylinder.
My thoughts on when and where to use the stuff. If you are going to race another car, by far the best place is at the track. I live a mile from a ¼ mile track. That makes it easy for me to say. When I use the stuff on the street it is only in these conditions. Always have your temperature gauge on and make sure your temperature is normal. No air conditioning for at least 5 -10 minutes before you spray so you’re under hood temperature can be as low as possible. I only race from a stop at a stop light up to the speed limit of that road which in my state is usually 50 to 55 mph for a four lane road. At that point one of you is faster than the other and both going faster isn’t going to change who is faster. If you have a stick you are basically spraying second gear from 3,500 rpm up to the speed limit. That is why to 75hp shot is ideal for the street, the maximum boost for a few seconds of spray. Then you’re done. Drive normally, if you spray again at the next traffic light you may backfire. It gives you the best chance to win and then it makes you drive normal or you blow up. At the track start with the 35hp for the first few runs. (I can speculate that the automatic shifts before the rev limiter kicks in, if you are not sure, I would shift at 6,000 rpm and not wait for the automatic to shift) Watch your temperature gauge when decelerating and coming back on the return lane. Then try the 50hp shot. Again watch your temperature gauge. If you notice higher or longer temp increases you may want to go back to the 35hp shot. Even though we all have the same car cooling systems we operate at different altitudes and temperatures. Remember there is no warning of a back fire, just operator prevention.
Arming Switches. You can find a 12 volt power source that is controlled by your ignition key in the fuse box under the hood. There are some spare terminals, just use a volt meter and a friend and check to find a terminal that is key controlled. Don’t worry about a fuse as you will use an inline fuse between the fuse box and the solenoids. I then put a “Valet Switch”. I mounted mine on the piece of plastic that covers the breaking hardware under the hood next to the fuse box. If you keep this switch off you cannot arm your system unless you open your hood. This keeps down the impromptu I’m going to get that guy road rage crap. Then I put an arming switch on the dash and a spray switch on my stick shift. In the old days you had a throttle cable that went to the carb or air intake butterfly. You could hook a micro switch up to the carb or butterfly and have a full throttle on or wide open throttle on switch. Cobalt’s do not have a throttle cable therefore you cannot hook up this switch. That is why I have a spray switch on the stick. This might not be comfortable for most people as if the Valet and Arming switches are on, there is no safety mechanism that would stop you from spraying at the wrong time. I turn the arming switch on right before I know I’m going to spray otherwise it’s always off. There are other safety devices such as a window switch which I assume connects to your computer and you set when it is OK to spray in parallel with some form of manual trigger. The basic lay out should look like this:
12 volt positive switched by the ignition key
Fuse (I think 15 amp)
In cab arming switch
In cab spray switch
All 4 switches are in series and must all be on to spray
Kits: I recommend the 4 – 6 cylinder universal wet fogger kits NOS, NX, Sniper all have kits. You will need a 4AN 18” female/female ended hose and a male/male fitting so that you can extend the fuel line that comes with the kit so that it reaches the fuel port on your injector rail.
Purge Kits: You can get them anywhere make sure you get 4AN size. Since I know when I’m going to run, I turn my bottle on then purge (the air) out of my system under full throttle in 2nd gear over 3,500 rpm. You will feel the boost when the air is purged and the nitrous is spraying. Then I race, when I’m going to shut the car off for a period of over 15 minutes I purge again (this time the nitrous) by shutting the valve off on the bottle and spraying at full throttle in 2nd gear over 3,500 rpm. As soon as you hit the spray you will feel the boost then 1 second later a lot less boost. You will still be spaying just gasoline and that does give a little boost. The reason for purging the system empty is that the solenoids can leak nitrous and fuel into your intake manifold, when you restart the car, there is a slight potential for backfire.
Gasoline: Always use premium. You never know when you might want to spray. The higher the octane, the less chance of pre-ignition/backfire.
Common Sense: Nitrous is a chemical reaction. It will work every single time. It doesn’t have feelings. It doesn’t know if it’s the right time or not, It’s kind of like Terminator. Since all the safety features are in your control, Think before you do.
The up side: I paid $11,000 for a base model 2007 LS Coup. The whole nitrous kit was less than $400.00 to fill the bottle is $50.00 the racing stripes were $500.00. For less than $12,000 I touch a switch and I go from 155hp to 230hp in a package that weighs less than 3,000 lbs. I may be nervous but I’m happy.